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I.
Compounds & Molecules
A. Compounds- made of atoms of more than
one element bound together.
1. Chemical bond- Attractive force that
holds atoms or ions together.
2. Compounds Vs. Mixtures
a) 2 or more elements bond together w/
different properties than originals.
b) Mixture- different substances are
just placed together and retain
original properties.
3. Formula & proportion
a) Compounds always have the same
chemical formula
ex: Salt NaCl H2O
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a)Compounds always have the same
elements in the same composition.
Ex: H2O
2 Hydrogen, 1 Oxygen.
4. Chemical Structure- the arrangement of
bonded atoms or ions within a
substance.
a)Determines properties of the
compound.
b)2 terms about position.
1)Bond length- Distance between
nuclei of 2 bonded atoms.
2)Bond angles-the orientation of 3
or more atoms.
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5. Models of compounds:
a)Ball-and-stick – Shows bond angle and
bond length. Figure 4-3
b)Space-filling - space occupied by
each atom. Figure 4-4
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B. Structure and Properties
1. Some compounds exist as a large network
of bonded atoms  repeating formula.
2. Network atoms structures
a) Strong solids  bonds are strong
Ex: Quartz in rocks  very strong,
rigid.
1)So strong that melting point(1700oC)
& boiling point(2230oC) is high.
b) Bonded ions
1)Strong network of repeating ions
a)Ex: NaCl
Na+ Cl- Na+ Cl- Na+ Clb)Strong attraction between
oppositely charged ions  high
melting point(801oC) & boiling
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point(1413oc).
3.
Compounds made of molecules
a) Molecule- smallest unit of a substance
the exhibits all the properties of
that substance.
b) Sugar- made of molecules C,H,O
1) Bonds between C,H,O are higher than
attraction between individual sugar
molecules.
II. Ionic & covalent bonds

Atoms bond when their electrons
interact.
A.
Ionic Bonds- a bond formed by
attraction between oppositely
ions. [metals (+) & nonmetals
1. Positive ions (Na+) attract
ions (Cl-)
the
charged
(-)]
negative
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2. 1 positive ion attracts several
negative ions  these negative
attracts positive ions => forms a
network of ions.
3. Formulas:
a)NaCl
Na+ 1
1:1 ratio
Cl- 1
b)CaF2
Ca2+ 1
1:2 ratio
F2
4. Conduct electicity
a)Solid ionic compounds cannot
conduct electricity because
charged ions are locked in place ~
Na+ Cl6
b)If dissolved in H2O, it doesn’t
conduct electricity  Because ions
are free to move.
B. Metallic Bonds- A bond formed by the
attraction between positively charged
metal ions & e- around them.
1. Metal’s nucleus is attracted to
neighboring e-  causes the atom to be
closely packed. Fig. 4-13
a)Energy levels overlap  e- move more
freely from atom to atom.
b)Explains why metals conduct
electricity so well.
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C. Covalent Bonds- a bond formed when atoms
share one or more pairs of electrons.
1. Networks of bonded atoms have covalent
bonds.
2. Can be solid,liquid,or gas; usually
between nonmetals.
3. Most have a low melting point < 300oC
4. Do not conduct electricity because they
are not charged.
5. Chlorine molecule, Cl2
a)Each Cl atom has 7 valence e- =>
needs 1 more.
b)Each Cl atom shares 1 e- => now each
Cl atom has full energy level.
c) e- are shared equally => nonpolar
covalent bond.
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6. Atoms may share more than 1 pair of ea)O2
1)6 valence e- => needs 2
2)So have 2 covalent bonds
O = O
b)N2
1)5 valence e- => needs 3
2)Has 3 covalent bonds
N ≡ N
3)Triple stronger than double bonds
7. Two different atoms sharing ea) e- are shared unequally => Polar
covalent bond.
b) e- usually more attracted to atoms
upper right of the periodic table.
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D. Polyatomic Ions- ion made of two or more
atoms that are covalently bonded and
that act like a single ion.
1. Ex:
a)Hydroxide OHb)Nitrate NO3c)Hydrogen carbonate ion HCO3d)Ammonium ion NH4+
2. Charge is for entire ion, not just
last atom
3. Ammonium sulfate
a)(NH4)2SO4 not N2H8SO4
b)Parenthesis show subscript applies
to entire ion.
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4. -ate Vs. –ite
a)Suffix –ate
1)Name the ion with the one more
oxygen atom.
2)EX: sulfate ion SO42nitrate ion NO3
b)Suffix –ite
1)Name the ion with one less oxygen
atom.
2)Ex: sulfite ion SO23nitrite ion NO2
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III. Compound names and formulas
A. Naming ions
1. Names of ionic compounds include the
ions of which they are composed.
a) Cation named stays the same
1) Ex: sodium Na+
b) Anion’s name changes its ending.
1) Ex: Fluorine  Fluoride Fnitrogen  Nitride N3c) NaF= Sodium Fluoride
CaCl2= Calcium Chloride
2. Transition Metals may form several
cations.
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a) Table 4-6
1)Copper (I) Cu+
Titanium (II) Ti2+
Copper (II) Cu2+
Titanium (III) Ti3+
Iron (II) Fe+
Titanium (IV) Ti4+
Iron (II) Fe3+
b) Cation is followed by a roman #
1)Roman number shows the charge
c) Ex: FeO
Vs. Fe2O3
O2iron(II)Oxide
iron(III)Oxide
d) Fe2O3
Fe3+
1)O has –2 charge + there are 3 of
them  -2 x 3 = -6
2)Ionic compounds must be neutral, so
need + 6
3)2 Fe atoms, so charge must be +3
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B. Naming Covalent Compounds
1. Numerical prefixes are used to name
covalent compounds of two elements.
a)Table 4-7 page 126
Prefixes for covalent Compounds
mono1
hexa6
di2
hepta7
tri3
octa8
tetra- 4
nona9
penta- 5
deca10
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b)Rules:
1)If only 1 atom for first element,
then no prefix (understood)
2)Element farthest to the right on
periodic table is second + ends in
–ide.
c)Examples:
1)BF3
 Boron triflouride
2)N2O4
 Dinitrogen tetroxide
2. Chemical Formulas for Covalent Compound
a)Empirical formula – simplest chemical
formula of a compound that tells the
smallest whole number ratio.
1)Water – H2O 2H:1O ratio
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2)Different compounds can have same
empirical formula
a. Examples:
i. Formaldehyde CH2O
CH2O
ii.Glucose
CH2O
C6H12O6
b)Molecular formula – formula that
reports the actual numbers of atoms
in one molecule of a compound.
1)Glucose
6C
12H 6O
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IV. Organic + Biochemical Compounds
A. Organic Compounds – covalently bonded
compound that contains Carbon.
1. Carbon forms four covalent bonds.
a) Hydrocarbon – contains C and
hydrogen.
1) Alkanes – hydrocarbons that have
only single covalent bonds.
a. Ends always in –ane.
b. Methane CH4
c. Ethane C2H6
d. Formula: CnH2n+2
e. Table 4-9 page 131
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2)Alkenes – have at least one double
bond between atoms.
a. Ends always in –ene.
b. Ethene C2H4
c. Propene C3H6
d. Formula: CNH2N
2. Alcohols – have a hydroxyl, or –OH
group bonded with it.
a. Methanol, CH3OH
b. Ethanol, C2H5OH
3. Polymers – large organic molecule made
of many smaller bonded units.
a)Examples:
1)Polyethene, milk jugs
poly = many , many ethenes 18
B. Biological Compounds
1. Carbohydrates – organic compound made
of carbon, hydrogen, and oxygen.
a)Provides energy for living things.
b)Glucose C6H12O6
2. Proteins and Amino Acids
a)Amino acids – 20 total
1)Made of Carbon, oxygen, hydrogen,
nitrogen, and sometimes sulfur.
b)Proteins – long chain of amino acids.
3. DNA – Deoxyribonucleic Acid
a)Made of C, H, O, Nitrogen, +
Phosphorus
b)Double Helix
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